Tank water heater



L wl c. M. QSERHEL@ PZSM@ TANK WATER HEATER Filed Jan. 27, 3.940 3 Sheets-Sheet l 6 l av k//A-CKLEY;

ZZBTMHL@ Amig L C. M. @STERHELD TANK WATER HEATER Filed Jan. 2'?, 3.940 3 Sheets-Smet 2 w. F. mm. m NfggN E R v5 o WUWW Y B CLAR/ g l@ @43 C. M. @@TERHEL@ 22375161@ TANK WATER HEATER Filed Jan. 27, 1940 5 Sheets-Shao?. 3

ATTORNEY Patented Apr. 1, 1941 TANK WATER HEATER Clark M. Osterheld, Stoughton, McGraw Electric Company,

ration of Delaware Wis., assigner to Elgin, Ill., a corpo- Application January 27, 1940, Serial No. 315,890

(Cl. 21S-39) 9 Claims.

My invention relates to water heaters and particularly to externally mounted electric heating units for hot water tanks.

One of the objects of my invention is to provide a simple and highly efficient electric heating unit for mounting on the outside of a hot water tank.

Another object of my invention is to provide a iiexible heating unit that is easily and quickly mountable in proper operative position against the outside of a tank and that is easily and quickly removable therefrom.

Other objects of my invention will either be apparent from a description of several forms embodying my invention or will be set forth' in the course of such description and particularly in the appended claims.

In the drawings,

Figure 1 is a vertical sectional View through a hot water tank and electric heating unit embodying my invention, taken on the line Il l of Fig. 2,

Fig. 2 is a horizontal sectional view taken the line 2 2 of Fig. l,

Fig. 3 is a fragmentary top plan view showing one tunnel and an electric heating unit positioned therein in proper operative position,

Fig. 4 is a horizontal sectional View thereof taken on the line 4 4 of Fig. 5,

Fig. 5 is a fragmentary vertical sectional View thereof taken on the line 5 5 of Fig. 3,

Fig. 6 is a View in side elevation of an electricinsulating bar supporting the resistor,

Fig. 7 is a View in front elevation of the bar shown in Fig. 6,

Fig. 8 is a top plan view of the electric heating unit embodying my invention as shown in Figs. 1 and 2,

Fig. 9 is a vertical View taken in section on the line 9 9 of Fig. 8, the heating units being shown in front elevation,

Fig. 10 is a vertical sectional View taken on the line Ill-I0 0f Fig. 8,

Fig. 11 is a top plan view of a still further on the line |6-l6 of Fig. 15, v

Fig. 17 is a section taken on the line H ll of Fig. 9 of the drawings, and

Fig. 1S is a. fragmentary sectional view taken on the line l8 l8 of Fig. 1.

The electric heating unit particularly embodying my invention as disclosed in the present application is particularly adapted for external mounting on the usual hot water tank 2| which hot water tank may be positioned within an outer casing 23, which may be of metal, and which is also provided with heat-insulating material 25 which may, for example, be of rock wool. The tank may be supported on legs 2l engaging a bottom plate 29, the tank 2i being spaced from the plate 29 by blocks 3| of heat-insulating material and made of any suitable or desired material, but shown in Fig. l of the drawings as being made of wood.

The tank is provided with a plurality of vertically extending tunnels 33 of which I have shown four, but I desire it to be understood that my invention is not limited to this specific number of tunnel members but that I may use either more or less depending upon the requirements of the installation or the demands of the purchaser desiring to operate a hot Water tank of this general kind. I have shown the tunnel members as being of substantially channel shape in lateral section of widened edge portions 35 and I have also shown the tunnel members as open at thetop and as closed at the bottom end thereof. I do not desire, however, to be limited to this since I may reverse the tunnels as to their open and closed ends and have the open end thereof at the bottom. While not limited thereto, I prefer to make the tunnel members 33 of metal and any suitable or desired means for securing the iiange portions 35 of the tunnel members into close heat-conducting relation against the outside of the tank may be employed and as an example of such means, I may mention the use of welding seams or of separated spot welds. The tunnel members may also be of any desired shape in lateral section as may be desired.

I may here point out that the construction of the heating units shown in Figs. 1 and 2 is the same as that shown in Figs. 8, 9, l0 and 17 of the drawings.

A flexible electric heating unit assembly is positioned in each of the tunnel members and each unit includes an elongated bar 3l of a. suitable electric-insulating material such as porcelain, lava or some other similar material. It is to be noted that the bars 31 are relatively thin and that they include a plurality of laterally-extending slots 39 spaced apart by portions filwhich may be considered, for example, as teeth which are longer laterally of the bar 31 than the rear portion thereof. In one form of the bars 31 one end is provided with a perforated central lug 53 while the other end of the baris provided with two spaced apart lugs d5, each of the lugs d3 and 45 being provided with an opening di extending therethrough for a purpose to be hereinafter referred to. A resistor 39 is positioned in the lateral slots 39 and extends beneath or around the overhanging end portions of the teeth di, all in a manner Well known in the art.

A modified form of bar 31, without the end lugs i3 and 55, as shown in section in Fig. 1'1 with the resistor wire d@ wound thereon, is positioned within a shroud member 5i, these shroud members being of substantially fiat channel shape in lateral section with relatively wide flange portions 53, the general outline of the respective shrouds in top view being shown particularly in Fig. 8 of the drawings. It is to be noted that the bars 31 are supported within the shrouds 5i as by bentover extensions 55 (see Fig. 10) although any other suitable or desired means for holding the bars in proper operative position within the shrouds may be used. While I have shown and described a specific form of heating element, I do not desire to be limited thereto as any other kind of heating element may be used.

The shrouds of channel shape may be provided with central curled end portions 51, one of these portions being provided at one end of the shroud and two spaced apart portions 51 being provided at the other end so that the adjacent heating units may be mechanically connected by-means of a pin 59 extending through the registering curled portions 51.

I provide further a pressure-transmitting member 6I which is also of substantially channel shape with its side edges engaging the flanges 53 so that upon pressure being applied centrally of the pressure member 6l, the flanges will be pressed into good heat conducting relation with the outside of the tank. The pressure-transmitting member 6l may be held in its proper operative position relatively to the shroud against which it is to be vpressed by a vertically-extending metal bar 63 which interiits with the mid-portion of the shroud and the end portions of which are bent around the respective ends of member 5i, reference being had to Fig. 17 of the drawings where such construction is shown in section.

Means for pressing the flanges 53 against the outside surface may include a vertically-extending shaft 65 having eccentrically mounted en larged cam portions 61 thereon either integral therewith or secured thereto, the members 51 being positioned at about the mid-portion of the pressure members 6i. The lower end of shaft 65 may t into an opening in a boss 69 provided in the bottom portion of the tunnel member 33 while the upper portion thereof may extend through a small plate 1l extending from the outer portion of the upper end of the tunnel member 33 over the opening formed by the tunnel member and the extreme upper end of shaft 55 may be provided with a square end to permit of manual turning of the shaft to force the cam member t1 tightly between the inner surface of the wall of a tunnel member 33 and the outer surface of the pressure-transmitting member 6 i.

Any desired number of such electric heating elements each including a bar supporting a resistor, a shroud closely operatively associated aesario therewith as shown particularly in Fig. l0 of the drawings, and a pressure member, may be supported from the upper edge of the tunnel member 33 as by the use of a rod 13 which rests upon the upper edge of the tunnel member 33.

Referring now to Figs. 3, 4 and 5 of the drawings, I have there illustrated a modied form of electric heating units each including a bar 31 having a heating resistor la mounted thereon as hereinbefore set forth in connection with the device shown in Figs. 8 to 10 inclusive, the bars 31 being provided with the projections d3 and l5 whereby they may be pivotally connected as by the use of a pin 15 shown more particularly in Fig 5 of the drawings. Shrouds 'i1 are provided, one for each bar 31, and it may be noted that each shroud is provided with rearwardly bent integral portions 1S cut out from the mid-portion of the flanges @i of the shrouds at each side thereof.

\ Means for causing tank engaging movement of the shrouds 11 include shafts B3 having enlarged eccentric portions thereon, a plurality of such portions being provided which are spaced apart a distance substantially equal to that of the width of the portions i9 whereby a shroud is supported on the upper ends of two portions 35 of the shafts 83, as is shown more particularly in Fig. 5 of the drawings. The shafts 83 may extend downwardly into the bottom end of the tunnel member in substantially the same manner as shown in Fig. l0 of the drawings while the upper ends of these shafts may extend through an opening in a corner plate 81, one of each such plates being provided at each outer corner of the tunnel member 33. This feature isshown particularly in Fig. 3 of the drawings. If, now, the squared upper ends of the shafts e3 are turned manually by an operator, the shrouds 11 which may originally be in the position shown in Fig. 4 of the drawings, will be moved into the position shown in Fig. 3 of the drawings where the ange portions 8i are in close operative engagement with the outside surface of the tank. The string of pivotally connected bars 3i, pivotally connected with each other as hereinbefore described, may be supported as by a rod 39 shown in Fig. 3 of the drawings as resting on the corner plates di.

Referring now to Figs. il and l2 of the drawings, I have there illustrated a further modiication of the device embodying my invention adapted to be mounted in a tunnel member 53 and including a plurality of bars 31 of electricinsulating material, a resistor is wound thereon and supported thereby and shroud members Si which are substantially the same as the shroud members 5l except that no curled-around end portions are provided at the respective ends thereof. However, the bars 5i are supported by eX- tensions 93 or" the shrouds at top and bottom in substantially the same manner as is shown in Fig. 10 of the drawings. A plurality of such heating units is held in proper operative longitudinal relation relatively to each other by a exible band of thin sheet metal having openings therein for receiving bent-over ears 91 punched from the shroud in substantially the same manner as is shown in Fig. 17 of the drawings for the rst described modification.

Here I provide somewhat dierent means for exerting pressure on the :danges 9g of the shrouds, this means including a pair of eccentrically mounted vertical shafts lill having short bottom end portions U93 fitting into a bearing and supporting lug H65 either integral with or secured to the tunnel member at its bottom en d while the upper end portions of the shafts I I extend through end portions IIII of a bracket IUS which, in addition to holding the upper ends of the pair of shafts IUI, is adapted also to support by a central extension III, the exible strip 95 whereby all of the 4series or string of heating units is suspended from the upper end of the tunnel member and supported thereby. It is obvious that turning movement of the extreme upper squared ends of the shafts IUI will cause engagement of the flanges 99 by the shafts IIII to press the flanges into close engagement with the outside surface of a tank and it is possible to obtain any desired degree of pressure against the outer surface of the tank.

Referring nowv to Figs. 13 and 14 of the drawings, I have there shown a still further medihcation of a device embodying my invention for pressing a plurality of shroud flanges against the outer surface of the tank. Each heating unit includes a bar 3l, resistor wire t9 therein, a shroud M3, anges H4 and a pressure-transmitting member M5 of the general kind hereinbefore described with the modication shown in Figs. 8 to 10 inclusive. The string of pivotally connected heating units is supported as by a rod iii extending through the curled-up upper end of the uppermost shroud itil, which rod rests upon the upper end of the side portions oi the tunnel member 33. l may Aprovide a plurality of wedges il@ either secured in proper position in the tunnel member 33 as shown in Fig. lli of the drawings, or I may connect these wedge members by any suitable means, such as a strip of metal, as may be thought desirable. i provide a second series of wedges iti connected by a rod i233 secured thereto in any suitable or desired manner, the rod i323 extending either through the respective wedges and secured thereto or secured against say the flat vertical surface thereof. It is to be noted that the rod H23 should be relatively heavy since its upper end has an adjusting screw 25 secured or extending therethrough which screw extends through a lug i2ll secured to the tunnel member adjacent its upper end so that turning movement ofc the upper end or' screw 925 will :force the string of wedges i2i connected by the rod ii, downwardly as shown in Fig. 1d oi the drawings, against the pressure-transmitting members M5 respectiveiy whereby the pressure members iid, each of substantially channel shape as hereinbeiore described, will cause close heat-conducting engagement of the flanges iid with the outside surface of the tank, the parts being shown in their 'proper operative position in top plan view in lFig. 13. may also make the compression rod i253 in the shape of a ten- Sion strip and. so arrange adjusting screw i225 that it will cause tensioning of the member cony necting the wedges i2i.

Referring now to Figs. i5 and i6, have there shown a still further modication particularly with relation to means for pressing the flanges of the respective shroud members into close heat-conducting engagement with the outside surface of a hot water tank. I provide a tunnel member il which is of slightly different form than that of tunnel member 33 but is adapted to be secured against the outside surface of the tank in any suitable or desired manner and as a metal member is preferably used, 4the outer edges thereof may be secured as by spot welds or welding seams. Each heating unit includes a bar 3l! having a resistor mounted therein as hereinbefore set forth and a shroud |33 having relatively wide flanges |35 of the same general character as hereinbefore described in connection with the other modification hereinbefore described. A pair of leaf springs I3I are provided, which leaf springs are initially bent to relatively fiat U- shape and may have their end portions slidable relative to the tunnel member and held in proper operative position by pins ISS adjacent the upper and lower ends of each spring. It is obvious that if a string of heating units of the kind hereinbefore described is lowered, say into an open-top tunnel member i3i, the respective anges |35 of the shrouds i33 will be forced into close heat-conducting relation with the outside surface of the tank 2i by these springs so that a heat-conducting path of relatively low thermal reluctance will be provided between the ilanges of the shrouds and the outer surface of the water tank.

As it may happen that a hot water tank of this kind is installed in the basement of a home with a relatively short distance between the upper end of the tank and the ceiling, which distance may be just sucient to permit of attaching additional piping to the hot water outlet pipe Mi, it is desirable to provide relatively simple means whereby a string of heating units in one or all of the tunnel members may be easily and quickly removed. `For this purpose I provide additional heat-insulating material 25 over the upper end of the tank iii and I provide a plurality of chambers M3 above the respective upper ends 0f the open-top'tunnel members 33, the height of each of these chambers being slightly larger than the overall length of each of the hereinbefore described heating units. Each of the chambers i453 defined, for instance, by side and inner walls constituting say a channel shaped member 1&5 (see Fig. i8) is provided with an easily removable door member il'i which, for in- Stance, may be held in place by a top screw M9 (see Fig. l). Should it be found necessary or desirable to remove a string of heating units from one of the tunnel chambers, the door member Edil may be removed and after manipulation of the shroud pressing means in any one of the various forms hereinbefore described to release the shroud members from their close operative engagement with the outer surface of the tank, it is possible to raise the string of heating units through the distance of one unit, that is the uppermost heating unit is moved into the cham ber i183. The connecting pin hereinbefore described as extending either through the electric insulating bars or through the end portions of the shrouds, may then be removed whereby the uppermost heating unit can easily be removed by simply cutting the connecting wire extending between the adjacent resistors. In the case of the rhodication shown in Figs. ll. and 12, it is only necessary that the heating unit irst positioned in chamber iill is moved into substantially horizontal position near the bottom of the chamber M3 after which the entire string may be raised so that the upper end or" the next lower heating unit is adjacent to the upper end oi the chamber when it will be possible to bend the strip continuation or" these steps permitting of removing the entire string through the opening in the chamber M3 formed by removal of the door ifll.

While I described hereinbefore a method oi disconnecting the uppermost heating unit when moved into the chamber H43, if desired, itis to be understood that a string of such heating units connected by the flexible band 95 can be eected in the same manner as hereinbefore described in connection with the modification shown in Figs. 11 and 12, it being only necessary to remove the individual heating units in sequence from the band Q5 as they are moved into the chamber M33.

While I have illustrated and described tunnel members which are open at the top to permit of insertion of heating units into the tunnel from the upper end of the tank and removal of the heating unitsthrough the upper end of the tunnel, I do not desire to be limited thereto since should it be found that the head room above the upper end of the tank is entirely too small, it ls easily possible to so arrange the installation that the tunnel members are open at their bottom ends and the heating units may be inserted into the respective tunnel members from the bottom ends thereof and may be removed therefrom through the lower open ends thereof. The string of heating units may in this case be supported say by restingr upon suitable means such as the bracket plate lS of Fig. 11 which is secured against the bottom end of the tunnel member, or by suitable supporting means secured to the upper end f the tunnel members. "1 Certain elements shown in the present application have been shown in my co-pendlng application Ser. No. 284,881 filed July 17, 1939, but it will be noted that in my earlier application the resiliently connected electric heating units extend in a horizontal plane around a hot Water tank while the present application shows them as extending substantially axially of a circular hot water tank. It is, of course, obvious that my invention is not limited to a circular tank but that a tank of square shape may have the heating units disclosed herein applied thereto and it is further obvious that the axis of the tank need not extend vertically but may also extend horizontally.

While I have shown several selected forms and modifications of electric heating units adapted for external mounting on a uid tank, it is obvious that my invention ils not limited thereto and I therefore desire that all further modications coming clearly within the scope of the appended claims shall be covered thereby.

I claim as my invention:

1. An electric tank heater assembly comprising a metal tunnel member extending longitudinally of the tank and having relatively wide side edges secured against the outside surface of the tank in good heat-conducting relation therewith,

. a plurality of elongated electric heating units positioned longitudinally in said tunnel member, each unit comprising a thin at block of electric insulating material having laterally-extending slots in that face thereof adjacent to the tank, a bare resistor` conductor in said slots. 'a metallic shroud of at channel shape at the back andthe sides of the block, relatively wide anges on the shroud at each side thereof, means vfor supporting all of said units from the tunnel member and means carried by the tunnel member and adjustable at one end of the tunnel member for pressing the flanges of all of the shrouds iito good heat-conducting contact with the outside surface of the tank to increase the effective surface area of the tank receiving heat from the resistor to a value appreclably greater than the area of the resistor-supporting block.

2. An electric tank heater assembly comprising a metal tunnel member extending axially of the tank and having its side edges secured against the outside surface of the tank in good heat-conducting relation therewith a plurality of elongated electric heating units extending longitudinally in said tunnel member, each unit comprising a thin flat block of electric insulating material having laterally-extending slots in one face thereof adjacent to the tank, a bare resistor conductor in said slots, a metallic shroud of fiat channel shape at the back and the sides of the block and having lateral longitudinally-extending relatively wide anges, means mechanically connecting said heating units in end-to-end relation whereby angular movement of the heating units relative to each other is effected, means for supporting all of said units from one end of the tunnel member and means operatively interposed between the tunnel member and the anges for pressing the anges of the several shrouds into good heat conducting contact with the outside surface of the tank whereby heat received by the shroud'from the block is conducted to the tank.

3, An electric heater assembly for mounting on a hot water tank comprising a straight tunnel member of substantially channel shape in lateral section extending vertically longitudinally of a tank against its outer surface, means securing its edges against the outer surface Iof a tank, a plurality of electric heating units in said tunnel member, each unit comprising a relatively thin bar of electric insulating material having laterally-extending slots in the face adjacent the outer surface of the tank, a bare resistor conductor in said slots, a. metallic shroud of at channed-shape at the back of said banthe shroud having a. longitudinally-extending relatively wide flange at each side thereof adapted to have flat face engagement with the tank, flexible means connecting said plurality of units in end-to-end series, means supporting said series of heating units from the upper end of the tunnel member and means supported by the tunnel member for pressing the flanges of the shrouds into good heat-conducting engagement with the outside surface of the tank.

4. A heater assembly for use on a hot water tank and comprising a straight tunnel member of substantially channel shape inA lateral section extending longitudinally of the tank secured to the outside of the tank and having at least one open end, a chamber structure adjacent the open end of the tunnel having a removableside door, alined with the open end of the tunnel member, a plurality of elongated electric heating units extending longitudinally in said tunnel member, each unit comprising a relatively thin bar of electric insulating material, a resistor carried by the bar adjacent to the outside surface of the tank, a metallic shroud of relatively flat channel shape and having lateral longitudinally-extending relatively wide flanges, located between the bar and the tunnel member, the length of each heating unit being less than the axial length of the chamber and disengageable flexible means connecting end portions of the heating units into a series to eiect removal of part or all of the units of a series one at a time through the chamber.

5. A heater assembly for use on a vertical hot water tank and comprising a tunnel member of substantially channel shape in lateral section secured to and extending vertically along the outside surface of the tank and having at least one open end,a chamber structure adjacent to the tank and to the open end of the tunnel member having a removable side door, a plurality of electric heating units suspended in said tunnel member and supported thereby, each unit comprising a relatively thin bar of electric insulating material, a resistor conductor carried by the bar adjacent to but spaced from the outside surface of the tank, a metallic shroud of dat channel-shape at the back of the bar and having side `iianges for engaging the surface of the tank, flexible means connecting the heating units in an end-to-end series and means operatively interposed between the tunnel member and the flanges of the shrouds for pressing the flanges into close heat-conducting engagement with the tank surface.

6. A device as set forth in claim 5 and including a pressure-transmitting member of substantially channel shape having its longitudinal edges engaging the side flanges of the shroud and in which the pressing means comprises a single eccentric shaft.

7. A device as set forth in claim 5 and including a pressure-transmitting member of substantially channel shape having its longitudinal edges engaging the side flanges of the shroud and in which the pressing means comprises a plurality of cooperating pairs of relatively-movable wedges between the tunnel member and the pressuretransmitting member.

8. A device as set forth in claim 5 in which the means for pressing the flanges of the shrouds against the tank includes a pair of eccentric shafts.

9. An electric tank heater assembly comprising a plurality of heating units, each comprising an elongated thin flat bar of electric-insulating material having slots in one face theerof, a resistor conductor in said slots in direct and close heat radiating relation to the outside surface of the tank, a metal shroud of high heat conductivity adjacent to the outer face of each bar having a relatively wide ange at each side positioned in fiat face engagement with the outside snrface of the tank, means pivotally connecting said heating units in an end-to-end series located axially of the tank, a metal tunnel member extending axially of the tank outside of said series of heating units and having relatively wide side edges held in at face close heat conducting relation to the outside surface of the tank, means supported at one end of the tunnel member for supporting the series of heating units and means interposed between the tunnel member and the anges for pressing the anges tightly into close heat-conducting engagement with the outside surface of the tank.

CLARK M. OS'I'ERHELD.- 

